Monday, March 14, 2011

Counting Carbon

Since the beginning of the anthropocene epoch, humans have released around 545 billion tons of carbon to the atmosphere from terrestrial and living storage reservoirs in the form of carbon dioxide (CO2). Scientists have been concerned with linkages between CO2 and climate since at least 1896, but only since 1992 has an international effort attempted to check CO2 emissions and limit the severity of anthropogenic climate changes (United Nations Framework Convention on Climate Change, UNFCCC).

The objective of the UNFCCC is to achieve ‘stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.’ CO2 currently accounts for 77% of global greenhouse gas emissions and is the focus of most greenhouse gas emissions accounting and reduction schemes.

Reducing global CO2 emissions in an equitable, timely manner is dauntingly complex. For example, there is rich debate on market-based mechanisms included in the Kyoto Protocol to incentivize emission reductions. These plans have led to a range of projects to reduce emissions that have been greeted with both hope and skepticism. Before any type of reduction plan can be effective though, we need to quantify when, where, and how much CO2 is being emitted. The remainder of this post is focused on the current international CO2 emissions accounting framework, critiques of this system, and alternative approaches that have been developed.

Territorial Accounting

The current international UNFCCC treaty framework allocates emissions spatially according to their point of injection into the atmosphere. Here’s an outline of the accounting process:

1. Nations are grouped into Annex 1 countries and non-Annex 1 countries based primarily on the condition of national economic development.

2. Annex 1 national governments are responsible for compiling and reporting CO2 emission inventories for emissions that originate from within national borders. Non-annex 1 countries voluntarily report emissions.

3. Emissions inventories from energy, industrial processes, agriculture, and land-use/forestry changes are compiled based on methodological standards set by the IPCC.

4. Each nation’s emissions inventories are subject to review by an independent expert assessment.

This territorial accounting system based on political borders is inherently producer-based, i.e. responsibility for emissions depends on the emission location rather than the location of demand and consumption that drives emissions. This approach is advantageous because political borders are usually recognizable and responsibility for emissions within national borders is assigned to national governments. In a globalized economy though, CO2 emission chains from energy and material extraction, production, transportation, consumption, and disposal usually extend well beyond regional and national political boundaries. These cross-border, global connections mean the geo-political approach is not airtight; there are gaps for ‘carbon leakage,’ i.e. CO2 emissions that escape accounting.

One source of leakage is CO2 from transportation and trade that crosses international boundaries and is emitted in international oceans and airspace. Currently these emissions are put into a storage bunker that doesn’t count towards a nation’s emissions totals. This bunker is an unregulated CO2 reservoir that potentially represents a significant loophole if emissions are creatively dumped here. From year 2000 to 2008, total CO2 emissions growth reported by Annex-1 nations was 1.5%, but the storage bunker holdings grew by 24.1%.

Another source of leakage in the political-boundary-approach is due to carbon outsourcing. This occurs when production and imbedded CO2 emissions are shifted from Annex 1 countries to non-Annex 1 countries with different emissions accounting requirements. This may result in emissions reductions for the outsourcing nation but from a global climate scale perspective, CO2 emitted in one location is the same as CO2 emitted in another. On a global scale, shifting emission locations amounts to a shell game that does little to reduce total emissions.

Consumer-based approaches

Defining scale boundaries in complex, continuous systems or networks is always tricky business and boundary selection is a fundamental issue in many disciplines such as geography, biology, economics, and sociology. In terms of anthropogenic CO2 emissions, consumptive goods typically have a long, geographically diffuse chain of emissions that crosses many political borders. Where along this chain should responsibility for emissions lie? How much responsibility does the consumer of a product have for the emissions generated during that product’s lifetime?

To address these questions, alternative approaches to emissions accounting have been developed. At scales of individual products, life-cycle analysis is a method that attempts to account for all CO2 emissions embodied in the production, consumption, use, and destruction of a product. On global scales, national input-output models account for emissions embodied in global trade and consumption, though this global view comes at the expense of detail. These approaches offer a more holistic view of CO2 emissions and could be used to facilitate sharing of responsibility for emissions between producers and consumers.

When CO2 emissions are considered from these life-cycle and consumer-based perspectives, it becomes clear that individual consumers and national governments have limited power to control emissions beyond their own borders. Labeling products with a carbon footprint has been proposed as a way to empower consumers.

It also becomes clear that CO2 emissions are part of a much larger, continuous global social-economic-technologic-agricultural-environmental system. Isolating a particular component of the system can yield important findings, but nothing exists in a vacuum. Serious efforts to reduce emissions will involve deep, system-wide changes and complex decisions on whether to channel limited resources towards mitigation options or adaptation strategies are ahead.